On Apr 19, 2007, at 6:08 PM, Tim Blechmann wrote: >>> i did some benchmarks of pd's phasor~ code against a straight- >>> forward >>> implementation on my pentium-m, when implementing the objects for >>> nova. >>> the straight-forward implementation ran about 20 to 30 % faster >>> than the >>> pd-style implementation. >> >> Do you still have the code from the straight forward implementation? > > i'm not sure, if i still have the benchmark code somewhere on my > machine, the phasor~/osc~ implementation can be found at > http://svn.klingt.org/nova/trunk/source/language/dsp/ > oscillator.cpp ... > > >>> code like sqare root or inverse square root can be coded by just >>> utilizing the rsqrtps and sqrtps opcodes, with a 14 bit precision, >>> when >>> working on the sse unit ... >> >> 14bit precision would leave a lot to be desired in Pd. Are there high >> precision operators? > > erm, according to the comments in d_math.c, miller's code only precise > for 8 mantissa bits and sqrt/rsqrt are aliases for q8_sqrt/q8_rsqrt > >>>> An alternative would be to special-case the offending code >>>> somehow. This >>>> could be part of a larger effort to make the DSP code modular so >>>> that SSE >>>> instructions and whatnot could also be "plugged in". Worth >>>> thinking about... >>> >>> according to the gcc manual, simple vectorizable operactions, that's >>> used for audio processing, can be autovectorized, if (and only >>> if) the >>> programmer takes care of both alignment and aliasing issues ... >> >> Is complying with -fstrict-aliasing enough to take care of the >> aliasing issues? > > aeh, no ... when referring to the term aliasing when talking about of > vectorizable functions, i'm referring to the aliasing of pointers as > function arguments ... > it should be described in the gcc manual in detail ...
Well, as you can see, this is not my area of expertise :). Thanks for the responses. At this point, I am mostly trying to get the issues out on the table so we can know how to proceed. .hc > > tim > > -- > [EMAIL PROTECTED] ICQ: 96771783 > http://tim.klingt.org > > Silence is only frightening to people who are compulsively > verbalizing. > William S. Burroughs ------------------------------------------------------------------------ ---- Access to computers should be unlimited and total. - the hacker ethic _______________________________________________ PD-dev mailing list [email protected] http://lists.puredata.info/listinfo/pd-dev
